Magnetic element having perpendicular anisotropy with enhanced efficiency

ABSTRACT

Techniques and magnetic devices associated with a magnetic element that includes a fixed layer having a fixed layer magnetization and perpendicular anisotropy, a nonmagnetic spacer layer, and a free layer having a changeable free layer magnetization and perpendicular anisotropy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application and claims priority under35 U.S.C. §120 to U.S. patent application Ser. No. 12/560,362, filed onSep. 15, 2009, which is now U.S. Pat. No. 8,072,800, the entire contentsof which are incorporated herein by reference.

BACKGROUND

This document relates to magnetic materials and structures having atleast one free ferromagnetic layer.

Various magnetic materials use multilayer structures which have at leastone ferromagnetic layer configured as a “free” layer whose magneticdirection can be changed by an external magnetic field or a controlcurrent. Magnetic memory devices may be constructed using suchmultilayer structures where information is stored based on the magneticdirection of the free layer.

One example for such a multilayer structure is a spin valve (SV) whichincludes at least three layers: two ferromagnetic layers and aconducting layer between the two ferromagnetic layers. Another examplefor such a multilayer structure is a magnetic or magnetoresistive tunneljunction (MTJ) which includes at least three layers: two ferromagneticlayers and a thin layer of a non-magnetic insulator as a barrier layerbetween the two ferromagnetic layers. The insulator for the middlebarrier layer is not electrically conducting and hence functions as abarrier between the two ferromagnetic layers. However, when thethickness of the insulator is sufficiently thin, e.g., a few nanometersor less, electrons in the two ferromagnetic layers can “penetrate”through the thin layer of the insulator due to a tunneling effect undera bias voltage applied to the two ferromagnetic layers across thebarrier layer.

Notably, the resistance to the electrical current across the MTJ or SVstructures varies with the relative direction of the magnetizations inthe two ferromagnetic layers. When the magnetizations of the twoferromagnetic layers are parallel to each other, the resistance acrossthe MTJ or SV structures is at a minimum value RP. When themagnetizations of the two ferromagnetic layers are anti-parallel witheach other, the resistance across the MTJ or SV is at a maximum valueRAP. The magnitude of this effect is commonly characterized by thetunneling magnetoresistance (TMR) in MTJs or magnetoresistance (MR) inSVs defined as (R_(AP)−R_(P))/R_(P).

SUMMARY

This document discloses techniques, devices and systems that usemagnetic elements that include at least a fixed magnetic layer havingperpendicular anisotropy, a nonmagnetic spacer layer, and a freemagnetic layer having perpendicular anisotropy which promotesmagnetization perpendicular to the plane of the magnetic layers. Thespacer layer resides between the fixed and free layers. The magneticelement is configured to allow the free layer to be switched using spintransfer when a write current is passed through the magnetic element.

In one aspect, methods and structures are disclosed to provideperpendicular anisotropy in a multilayer magnetic element. In oneimplementation, a fixed layer is provided to have a fixed layermagnetization fixed in a direction perpendicular to the fixed layer, anonmagnetic spacer layer is provided over the fixed layer, and a freelayer is located relative to the fixed layer and the spacer layer sothat the spacer layer is between the free and fixed layer. The freelayer has a free layer magnetization that is perpendicular to the freelayer and is changeable relative to the fixed layer magnetization. Aninterfacial layer is in contact with the spacer layer and is a magneticlayer. A connecting layer is in contact with the interfacial layer andthe free layer. The connecting layer has a structure providing magneticcoupling between the free layer and the interfacial layer that maintainsthe magnetization of the interfacial layer to be perpendicular to theinterfacial layer and providing a separation between the free layer andthe interfacial layer to permit the free layer and the interfacial layerto have different material structures.

The free layer and/or the fixed layer are configured to haveperpendicular anisotropy. In certain implementations, the free layerand/or the fixed layer could include ferromagnetic (Ni, Fe,Co)_(100-y)(Pd, Pt)_(y) where y ranges between twenty and eighty atomicpercent, or between fifty and seventy five atomic percent.

In certain implementations, the free layer and/or the fixed layer havingperpendicular anisotropy could include ferromagnetic material (Ni, Fe,Co)₅₀(Pd, Pt)₅₀ combined with nonmagnetic material(s). In certainimplementations the nonmagnetic material(s) could include at least oneof Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag,Cu. In certain implementations the nonmagnetic material(s) could includeat least one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, anitride, or a transition metal. In certain implementations thenonmagnetic material(s) could include at least one Ti, Zr, Hf, V, Nb,Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu and at least oneof B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, a nitride, or atransition metal silicide.

In certain implementations, the free layer and/or the fixed layer havingperpendicular anisotropy could include ferromagnetic material Ni, Fe, oran alloy of Ni, Fe, and/or Co including at least Ni and/or Fe combinedwith nonmagnetic material(s). In certain implementations the nonmagneticmaterial(s) could include at least one of Ti, Zr, Hf; V, Nb, Ta, Cr, Mo,W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu, B, C, N, O, Al, Si, P, S, Ga,Ge, In, Sn, Gd, Tb, Dy, Ho, Nd, an oxide, a nitride, or a transitionmetal silicide.

In certain implementations, the free layer and/or the fixed layer havingperpendicular anisotropy could include ferromagnetic material (Ni, Fe,Co) combined with nonmagnetic material(s). In certain implementationsthe nonmagnetic material(s) could include at least one of Cr, Ta, Nb, V,W, Hf, Ti, Zr, Pt, Pd, Gd, Tb, Dy, Ho, Nd, and at least one of Ti, Zr,Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu. Incertain implementations the nonmagnetic material(s) could include atleast one of Cr, Ta, Nb, V, W, Hf, Ti, Zr, Pt, Pd, Gd, Tb, Dy, Ho, Nd,and at least one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide,a nitride, or a transition metal silicide.

In certain implementations, the free layer and/or the fixed layer havingperpendicular anisotropy could include material Mn, and/or including atleast Ni, Al, Cr, and/or Fe combined with nonmagnetic material(s). Incertain implementations the nonmagnetic material(s) could include atleast one of Ti, Zr, Hf; V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os,Re, Au, Ag, Cu, B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, Gd, Tb, Dy,Ho, Nd, an oxide, a nitride, or a transition metal silicide.

In certain implementations, the free layer and/or the fixed layer havingperpendicular anisotropy could include a multilayer includingalternating layers of magnetic material layers and nonmagnetic materiallayers. In certain implementations the magnetic material layers includes(Ni, Fe, Co) and the nonmagnetic material layers include at least one ofTi, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag,Cu. In certain implementations the magnetic material layers includes(Ni, Fe, Co) and the nonmagnetic material layers include at least one ofB, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, a nitride, or atransition metal silicide. In certain implementations the magneticmaterial layers includes (Ni, Fe, Co)₅₀(Pd, Pt)₅₀ and the nonmagneticmaterial layers include at least one of Cr, Pt, Pt, Pd, Ir, Rh, Ru, Os,Re, Au, Cu. In certain implementations the magnetic material layersincludes (Ni, Fe, Co) combined with at least one of Cr, Pt, Pd, Ir, Rh,Ru, Os, Re, Au, Cu. In certain implementations the magnetic materiallayers includes (Ni, Fe, Co) combined with at least one of Cr, Ta, Nb,V, W, Hf, Ti, Zr, Pt, Pd and the nonmagnetic material layers include atleast one of Cr, Pt, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Cu. In certainimplementations the magnetic material layers includes (Ni, Fe, Co)combined with at least one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Snand the nonmagnetic material layers include at least one of Cr, Pt, Pt,Pd, Ir, Rh, Ru, Os, Re, Au, Cu. In certain implementations the magneticmaterial layers includes (Ni, Fe, Co) combined with at least one of Cr,Ta, Nb, V, W, Hf, Ti, Zr, Pt, Pd and the nonmagnetic material layersinclude at least one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, anoxide, a nitride, or a transition metal silicide.

In another aspect, a device is provided to include a magnetic elementarray including a substrate and magnetic elements formed on thesubstrate. Each magnetic element includes a fixed layer having a fixedlayer magnetization fixed in a direction perpendicular to the fixedlayer, a nonmagnetic spacer layer over the fixed layer, an interfaciallayer in contact with the spacer layer and being a magnetic layer, aconnecting layer in contact with the interfacial layer, and a free layerin contact with the connecting layer and having a free layermagnetization that is perpendicular to the free layer and is changeablerelative to the fixed layer magnetization based on spin torque transfer.The connecting layer has a structure providing magnetic coupling betweenthe free layer and the interfacial layer that maintains themagnetization of the interfacial layer to be perpendicular to theinterfacial layer and providing a separation between the free layer andthe interfacial layer to permit the free layer and the interfacial layerto have different material structures. This device includes a circuitthat is coupled to the magnetic element array and supplies a current toflow through layers of each magnetic element in a directionperpendicular to the layers to switch the magnetization of the freelayer based on spin torque transfer between two magnetizationdirections.

These and other implementations are described in greater detail in thedrawings, the description and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an example of a magnetic element in the form a spin valve.

FIG. 1B shows an example of a magnetic element in the form of a spintunneling junction.

FIGS. 2A and 2B depict examples of two magnetic elements havingperpendicular anisotropy with fixed layer below and above thenonmagnetic spacer.

FIGS. 3A, 3B and 3C show examples of magnetic elements having aperpendicular anisotropy based on one or more interfacial layers.

FIGS. 4A, 4B and 4C show two examples of magnetic elements having aperpendicular anisotropy based on interfacial and connecting layers.

FIG. 5 depicts an example of a device of an array of magnetic elementseach having a perpendicular anisotropy based on interfacial andconnecting layers.

FIG. 6 depicts an example of a magnetic element having a perpendicularanisotropy free layer and/or fixed layer connected to a bit line and anisolation device.

FIG. 7 depicts an exemplary implementation of the device in FIG. 6illustrating a circuit that operates the device based on spin-transfertorque switching with a perpendicular anisotropy free layer and/or fixedlayer.

DETAILED DESCRIPTION

Multilayered magnetic elements with a free layer and a fixed layerseparated by a nonmagnetic spacer, when grown monolithically on asubstrate, require certain material properties of adjacent layers to becompatible or match, e.g., match of lattice structures. This can limitthe choice of materials suitable for forming such structures and thusaffect the properties of the constructed magnetic elements. Examples ofmultilayered magnetic elements described in this document have amagnetization perpendicular to the free and fixed layers and includeadditional layers between at the free layer and the spacer layer toengineer desired properties of the magnetic elements, e.g., increasingthe TMR ratio, achieving a high STT efficiency and reducing the dampingconstant.

The following sections first describe structures of magnetic elementsand then provide examples of magnetic elements with a perpendicularmagnetization and the additional layers for engineering the magneticelements.

FIGS. 1A and 1B depict exemplary magnetic elements 10 and 10′ formed ona substrate 1. The magnetic element 10 is a spin valve and includes anantiferromagnetic (AFM) layer 12, a fixed layer 14, a conductive spacerlayer 16 and a free layer 18. Other layers, such as seed or cappinglayer can also be used. The fixed layer 14 and the free layer 18 areferromagnetic. The free layer 18 is depicted as having a changeablemagnetization 19. The magnetization of the free layer 18 is free torotate, in response to an external magnetic field, a driving electriccurrent, or a combination of both. The conductive spacer layer 16 isnonmagnetic. The AFM layer 12 is used to pin the magnetization of thefixed layer 14 in a particular direction. After post annealing, theferromagnetic layer 14 is pinned with a fixed magnetization 15. Alsodepicted are top contact 20 and bottom contact 22 that can be used todrive current through the magnetic element 10.

The magnetic element 10′ depicted in FIG. 1B is a magnetic tunnelingjunction. The magnetic element 10′ includes an AFM layer 12′, a fixedlayer 14′ having a fixed layer magnetization 15′, an insulating barrierlayer 16′, a free layer 18′ having a changeable magnetization 19′. Thebarrier layer 16′ is thin enough for electrons to tunnel through in amagnetic tunneling junction 10′.

The relationship between the resistance to the current flowing acrossthe MTJ or SV and the relative magnetic direction between the twoferromagnetic layers in the TMR or MR effect can be used for nonvolatilemagnetic memory devices to store information in the magnetic state ofthe magnetic element. Magnetic random access memory (MRAM) devices basedon the TMR or MR effect, for example, can be an alternative of andcompete with electronic RAM devices. In such devices, one ferromagneticlayer is configured to have a fixed magnetic direction and the otherferromagnetic layer is a “free” layer whose magnetic direction can bechanged to be either parallel or opposite to the fixed direction andthus operate as a recording layer. Information is stored based on therelative magnetic direction of the two ferromagnetic layers on two sidesof the barrier of the MTJ or SV. For example, binary bits “1” and “0”can be recorded as the parallel and anti-parallel orientations of thetwo ferromagnetic layers in the MTJ or SV. Recording or writing a bit inthe MTJ or SV can be achieved by switching the magnetization directionof the free layer, e.g., by a writing magnetic field generated bysupplying currents to write lines disposed in a cross stripe shape, by acurrent flowing across the MTJ or SV based on the spin transfer effect,by a combination of applying both a writing magnetic field and acurrent, or by other means.

Magnetic random access memory devices utilizing a spin transfer effectin switching can be operated under a low switching current density,J_(c), below 10⁷ A/cm² (e.g., around or below 10⁶ A/cm²) for practicaldevice applications. This low switching current density advantageouslyallows for formation of densely packed memory cells (e.g., sub-micronlateral dimensions) with a high bias current. The reduction ofspin-transfer switching current density J_(c) can be critical for makingMRAM devices featured by a fast operation speed, low power consumption,and a high spatial density of memory cells. With decreased technologynode of memory devices, however, thermal stability decreases andincreasingly affects the performance of these devices. During periods oflatency when an MTJ preserves a stored datum, the magnetization in thefree layer is not entirely static and may change due to thermalfluctuations that allow the magnetic moments within the free layer tooscillate or precess. The random nature of these fluctuations allows theoccurrence of rare, unusually large fluctuations that may result in thereversal of the free-layer magnetization.

Magnetic materials with perpendicular anisotropy can be used to provideincreased thermal stability in magnetic devices, including spin transfermagnetic devices. In these devices, the thermal activation factordepends on the volume and perpendicular magnetic anisotropy of the freelayer of a magnetic element and the thermal stability decreases as thevolume of the magnetic element reduces. The large perpendicularanisotropy can compensate for the reduced thermal stability due to thedecrease in volume associated with the decreasing device size. Inaddition, for spin transfer devices utilizing perpendicular anisotropy,the in-plane shape anisotropy is no longer required in the devicedesign. Accordingly, the device shape can be circular instead of anelongated shape to improve the memory device areal density.

Based on a spin transfer model, the switching current density can beexpressed for the films having out-of-plane or perpendicular dominantanisotropy in the absence of external field as:J_(c)∝αM_(s)t(H_(⊥)−4πMs)/ηwhere α is the phenomenological Gilbert damping, t and M_(s) are thethickness and saturation magnetization of the free layer, respectively.H_(⊥) is intrinsic perpendicular uniaxial anisotropy field which couldbe resulted from interfacial (or surface) anisotropy and/or effect ofmagneto-elastic energy. η corresponds to an efficiency of spin transferswitching. 4πMs comes from demagnetization field perpendicular to thefilm plane.

The absolute value of H_(⊥) is generally larger than that of 4 Ms forthe case of the film having out-of-plane perpendicular anisotropy.Therefore, the term of (H_(⊥)−4 Ms) and the associated switching currentdensity Jc, can be reduced through optimization of H_(⊥) of the freelayer in the case of the films having perpendicular anisotropy. Inaddition, a reduction of magnetization Ms of the free layer can be usedto reduce the switching current density Jc.

The examples of magnetic devices based on a magnetic element havingperpendicular magnetization layers can be switched with the spintransfer effect. The small spin-transfer switching current and high readsignal can be achieved by using the perpendicular magnetization in spinvalve and magnetic tunnel junction films.

FIG. 2A depicts one implementation of a magnetic element 100 on asubstrate 1. This magnetic element 100 includes a free layer 130 on thetop and a fixed layer 110 on the bottom, both with perpendicularanisotropy. A nonmagnetic spacer layer 120 is formed between the layers110 and 130. The fixed layer 110 has a fixed layer magnetization 111perpendicular to the fixed layer 110, and the free layer 130 has areversible free layer magnetization 131 perpendicular to the free layer130. The free layer magnetization 131 can be written using the spintransfer effect. In this example, the fixed layer 110 is undernonmagnetic spacer layer 120 and above the substrate 1 and the freelayer 130 is above the nonmagnetic spacer layer 120. Fixed layer 110and/or free layer 130 can include magnetic materials multilayered withnonmagnetic or oxide layers, in which the magnetic sublayers can beantiferro-magnetically or ferro-magnetically coupled. Nonmagnetic spacerlayer 120 can include insulating layers such as Al₂O₃, MgO, TiO, TaO,and other oxides. Nonmagnetic spacer layer 120 can include conductinglayers such as Cu. An antiferromagnetic layer can be included to pin themagnetization of the fixed layer magnetization 111 in a desireddirection after post annealing.

FIG. 2B depicts another implementation of a magnetic element 100′ on asubstrate 1 having a free layer and a fixed layer, both withperpendicular anisotropy. The magnetic element 100′ includes a fixedlayer 110′ having a fixed layer magnetization 111′, a nonmagnetic spacerlayer 120′, and a free layer 130′ with magnetization 131′ that can bewritten using spin transfer. The fixed layer 110′ is above nonmagneticspacer layer 120′ and the free layer 130′ is under the nonmagneticspacer layer 120′ and above the substrate 1. Fixed layer 110′ and/orfree layer 130′ can include magnetic materials multilayered withnonmagnetic or oxide layers, in which the magnetic sublayers can beantiferro-magnetically or ferro-magnetically coupled. Nonmagnetic spacerlayer 120 can include insulating layers such as Al₂O₃, MgO, TiO, TaO,and other oxides. Nonmagnetic spacer layer 120′ can include conductinglayers such as Cu. An antiferromagnetic layer can be included to pin themagnetization of the fixed layer magnetization 111 in a desireddirection after post annealing.

A capping layer can be included above free layer 130 in FIG. 2A and thefixed layer 110′ in FIG. 2B. Also, a seed layer can be included betweenthe fixed layer 110 and the substrate 1 in FIG. 2A and between the freelayer 130′ and the substrate 1 in FIG. 2B. Both the capping layer andseed layer can be a single layer or multilayer in structure, crystallineor amorphous in state, metal or oxide, magnetic or non-magnetic, eitherwith in-plane or with perpendicular anisotropy. The capping layer and/orseed layer can be at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt,Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu; or B, C, N, O, Al, Si, P, S or theiralloying, or oxide, nitride or silicide with transition metal, such asAlMg, CrTi, CrMo, CrRu, NiAl, NiP, NiFeCr, MgO, TaO, TiO, AlO, SiO,CuAlO, TiN, TaN, CuN, FeSi, CoO, NiO. The capping layer and/or seedlayer can improve texture for perpendicular properties, improveinterfacial properties for stack growth and tunneling magnetoresistance,act as a stop layer for interdiffusion, provide protection cover orcoating for stack stability, and/or shield the magnetic layers fromstray magnetic fields.

In FIG. 2A, the magnetic layer with perpendicular anisotropy can beimplemented by providing a free layer and/or a fixed layer that includesa ferromagnetic material and nonmagnetic material. To obtain the freelayer 130 and/or the fixed layer 110 with perpendicular anisotropy, aferromagnetic material and a nonmagnetic material can be combined in asingle ferromagnetic layer used in or for the free layer 130 and/or thefixed layer 110. Thus, the free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be made by combining ferromagnetic andnonmagnetic materials. Further, free layer 130 and/or the fixed layer110 with perpendicular anisotropy can be provided by providing a freelayer that includes a multilayer of magnetic and nonmagnetic layers.

In FIG. 2B, the magnetic layer with perpendicular anisotropy can beimplemented by providing a free layer and/or a fixed layer that includesa ferromagnetic material and nonmagnetic material. To obtain the freelayer 130′ and/or the fixed layer 110′ with perpendicular anisotropy, aferromagnetic material and a nonmagnetic material can be combined in asingle ferromagnetic layer used in or for the free layer 130′ and/or thefixed layer 110′. Thus, the free layer 130′ and/or the fixed layer 110′with perpendicular anisotropy can be made by combining ferromagnetic andnonmagnetic materials. Further, free layer 130′ and/or the fixed layer110′ with perpendicular anisotropy can be provided by providing a freelayer that includes a multilayer of magnetic and nonmagnetic layers.

In one implementation, a free layer 130 and/or the fixed layer 110 withperpendicular anisotropy can be provided with ferromagnetic material(Ni, Fe, Co)_(100-y)(Pd, Pt)_(y) where y ranges between twenty andeighty atomic percent, or between fifty and seventy five atomic percent.Here, (Ni, Fe, Co) denotes Ni, Fe, Co, or an alloy of Ni, Fe, and/or Co.Likewise, (Pd, Pt) denotes Pd, Pt or an alloy of Pd and Pt. For example,in this implementation, free layer 130 and/or the fixed layer 110 can becomprised of Co₅₀Pt₅₀ or Co₅₀Pd₅₀. Free layer 130 and/or fixed layer 110can include magnetic materials multilayered with nonmagnetic or oxidelayers, in which the magnetic sublayers can be antiferro-magnetically orferro-magnetically coupled.

In a second implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by combining ferromagneticmaterial (Ni, Fe, Co)₅₀(Pd, Pt)₅₀ with material X, where X includes atleast one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os,Re, Au, Ag, Cu. In one implementation, X ranges between zero and fiftyatomic percent in content. For example, in this implementation, freelayer 130 can be comprised of Co45Pd55, Co45Pd45Cu10, Co45Pd45Re10. Freelayer 130 and/or fixed layer 110 can include magnetic materialsmultilayered with nonmagnetic or oxide layers, in which the magneticsublayers can be antiferro-magnetically or ferro-magnetically coupled.

In a third implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by combining ferromagneticmaterial (Ni, Fe, Co)₅₀(Pd, Pt)₅₀ with material X, where X includes atleast one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, anitride, or a transition metal. In one implementation, X ranges betweenzero and fifty atomic percent in content. Free layer 130 and/or fixedlayer 110 can include magnetic materials multilayered with nonmagneticor oxide layers, in which the magnetic sublayers can beantiferro-magnetically or ferro-magnetically coupled.

In a fourth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by combining ferromagneticmaterial Ni, Fe, or an alloy of Ni, Fe, and/or Co including at least Niand/or Fe with material X, where X includes at least one of Ti, Zr, Hf;V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu, B, C, N,O, Al, Si, P, S, Ga, Ge, In, Sn, Gd, Tb, Dy, Ho, Nd, an oxide, anitride, or a transition metal silicide. In one implementation, X rangesbetween zero and eighty atomic percent in content. Free layer 130 and/orfixed layer 110 can include magnetic materials multilayered withnonmagnetic or oxide layers, in which the magnetic sublayers can beantiferro-magnetically or ferro-magnetically coupled.

In a fifth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by combining ferromagneticmaterial (Ni, Fe, Co)₅₀(Pd, Pt)₅₀ with materials X and Y; where Xincludes Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re,Au, Ag, Cu; and where Y includes at least one of B, C, N, O, Al, Si, P,S, Ga, Ge, In, Sn, an oxide, a nitride, or a transition metal silicide.In one implementation, X ranges between zero and fifty atomic percent incontent. In one implementation, Y ranges between zero and fifty atomicpercent in content. Free layer 130 and/or fixed layer 110 can includemagnetic materials multilayered with nonmagnetic or oxide layers, inwhich the magnetic sublayers can be antiferro-magnetically orferro-magnetically coupled.

In a sixth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by (Ni, Fe, Co) withmaterials X and Y; where X includes Cr, Ta, Nb, V, W, Hf, Ti, Zr, Pt,Pd, Gd, Tb, Dy, Ho, Nd; and where Y includes Ti, Zr, Hf; V, Nb, Ta, Cr,Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu. In one implementation, Xand/or Y ranges between zero and eighty atomic percent in content. Freelayer 130 and/or fixed layer 110 can include magnetic materialsmultilayered with nonmagnetic or oxide layers, in which the magneticsublayers can be antiferro-magnetically or ferro-magnetically coupled.

In a seventh implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by (Ni, Fe, Co) withmaterials X and Y; where X includes Cr, Ta, Nb, V, W, Hf, Ti, Zr, Pt,Pd, Gd, Tb, Dy, Ho; and where Y includes at least one of B, C, N, O, Al,Si, P, S, Ga, Ge, In, Sn, an oxide, a nitride, or a transition metalsilicide. In one implementation, X and/or Y ranges between zero andeighty atomic percent in content. Free layer 130 and/or fixed layer 110can include magnetic materials multilayered with nonmagnetic or oxidelayers, in which the magnetic sublayers can be antiferro-magnetically orferro-magnetically coupled.

In an eighth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by a multilayer comprisedof alternating layers of magnetic material and material Y, where thelayers of magnetic material include (Ni, Fe, Co) and Y includes Ni, Fe,Co, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au,Ag, Cu. Y can be thinner, equal, or thicker than the magnetic layers inthickness.

In a ninth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by a multilayer comprisedof alternating layers of magnetic material and material Y, where thelayers of magnetic material include (Ni, Fe, Co) and Y includes at leastone of Ni, Fe, Co, B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, anitride, or a transition metal silicide. Y can be thinner, equal, orthicker than the magnetic layers in thickness.

In a tenth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by a multilayer comprisingof alternating layers of magnetic material and nonmagnetic material,where magnetic material layers include ferromagnetic material (Ni, Fe,Co)₅₀(Pd, Pt)₅₀ and nonmagnetic material layers include material X whereX includes Cr, Pt, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Cu. The nonmagneticmaterial layers can be thinner, equal, or thicker than the magneticlayers in thickness.

In an eleventh implementation, a free layer 130 and/or the fixed layer110 with perpendicular anisotropy can be provided by a multilayercomprising of alternating layers of magnetic material and nonmagneticmaterial, where magnetic material layers are provided by combiningferromagnetic material (Ni, Fe, Co) with material X where X includes Cr,Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Cu. The nonmagnetic material layers canbe thinner, equal, or thicker than the magnetic layers in thickness.

In a twelfth implementation, a free layer 130 and/or the fixed layer 110with perpendicular anisotropy can be provided by a multilayer comprisedof alternating layers of magnetic material and material Y, where thelayers of magnetic material are provided by combining ferromagneticmaterial (Ni, Fe, Co) with material X where X includes Cr, Ta, Nb, V, W,Hf, Ti, Zr, Pt, Pd and Y includes Cr, Pt, Pt, Pd, Ir, Rh, Ru, Os, Re,Au, Cu. Y can be thinner, equal, or thicker than the magnetic layers inthickness.

In a thirteenth implementation, a free layer 130 and/or the fixed layer110 with perpendicular anisotropy can be provided by a multilayercomprised of alternating layers of magnetic material and material Y,where the layers of magnetic material are provided by combiningferromagnetic material (Ni, Fe, Co) with material X where X includes atleast one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn and Y includes Cr,Pt, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Cu. Y can be thinner, equal, orthicker than the magnetic layers in thickness.

In a fourteenth implementation, a free layer 130 and/or the fixed layer110 with perpendicular anisotropy can be provided by a multilayercomprised of alternating layers of magnetic material and material Y,where the layers of magnetic material are provided by combiningferromagnetic material (Ni, Fe, Co) with material X where X includes Cr,Ta, Nb, V, W, Hf, Ti, Zr, Pt, Pd and Y includes at least one of B, C, N,O, Al, Si, P, S, Ga, Ge, In, Sn, an oxide, a nitride, or a transitionmetal silicide. Y can be thinner, equal, or thicker than the magneticlayers in thickness.

In a fifteenth implementations, the free layer and/or the fixed layerhaving perpendicular anisotropy could include material Mn, and/orincluding at least Ni, Al, Cr, Co, and/or Fe combined with nonmagneticmaterial(s). In certain implementations the nonmagnetic material(s)could include at least one of Ti, Zr, Hf; V, Nb, Ta, Cr, Mo, W, Pt, Pd,Ir, Rh, Ru, Os, Re, Au, Ag, Cu, B, C, N, O, Al, Si, P, S, Ga, Ge, In,Sn, Gd, Tb, Dy, Ho, Nd, an oxide, a nitride, or a transition metalsilicide.

The above implementations can be applied to the fixed layer 110′ and/orthe free layer 130′ in FIG. 2B.

Because the current required to switch a magnetic element by the spintransfer effect depends on the difference between the anisotropy fieldand the demagnetization field of the free magnetic layer, introducingperpendicular anisotropy can provide the benefit of lowering the spintransfer switching current. Moreover, the control of the composition ofthe magnetic elements in some implementations can modify the Curietemperature and magnetic moment of the magnetic material which canachieve the benefits of lower spin transfer switching current andincreased thermal stability. Further, the control of the composition ofthe magnetic elements in some implementations can improve the filmgrowth, which may lead to an improved overall performance of themagnetic elements and devices.

In perpendicular magnetic elements in FIG. 2A, the free layer 130 is indirect contact with the spacer layer 120. As such, the materials for thefree layer 130 and the spacer layer 120 need to be matched in theirlattice structures. This restriction can limit the materials suitablefor forming such structures and thus the properties of the constructedmagnetic elements. For example, some perpendicular MTJ devices based onthe design in FIGS. 2A and 2B use materials that exhibit an undesiredhigh damping constant, low STT efficiency and low TMR ratio. A Low TMRratio, in turn, causes a undesired low read speed for STT-RAM chip and alow STT efficiency causes a undesired high STT switching current.

Implementations of perpendicular magnetic elements described belowinclude a fixed layer having a fixed layer magnetization fixed in adirection perpendicular to the fixed layer, a nonmagnetic spacer layerover the fixed layer and a free layer. In addition, one or moreadditional layers are included between the spacer layer and the freelayer and/or between the spacer layer and the fixed layer to engineerdesired properties of the magnetic elements, e.g., increasing the spintransfer efficiency and enhancing the perpendicular magnetization. Suchone or more additional layers form a intermediary between the spacerlayer and at least one of the free layer and the fixed layer to allowvarious magnetic materials to be used for either the free layer or thefixed layer to achieve desired properties of the magnetic element.

In some implementations, one or more interfacial layers can be providedto be in contact with the spacer layer. Such an interfacial layer is athin layer of a magnetic material that exhibits a magnetizationperpendicular to the interfacial layer. This interfacial layer can besufficiently thin, e.g., under or around 1 nm, to maintain itsmagnetization to be perpendicular to the layers in the magnetic elementvia magnetic coupling with the free layer and the fixed layer.

FIGS. 3A, 3B and 3C show three examples of magnetic elements withperpendicular magnetization having such additional layers. In the device200 in FIG. 3A, the free layer is the magnetization layer 250 with aperpendicular magnetization 251 that can be switched between twoperpendicular directions. The fixed layer is the magnetization layer 210with a fixed perpendicular magnetization 211. The non-magnetic spacerlayer 220 is located between the free layer 250 and the fixed layer 210.An additional magnetization layer 230, an interfacial layer, is providedbetween the free layer 250 and the spacer layer 220 to provide anintermediary between the free layer 250 and the spacer layer 220 and hasa perpendicular magnetization 231 that is magnetically pinned to themagnetization 251 of the free layer 250 to switch with the free layer250 based on the spin torque transfer. The thickness of the interfaciallayer 230 is sufficiently thin, e.g., less than 1 nm, to allow themagnetization 231 to be strongly coupled to the magnetization 251 of thefree layer 250. The presence of the interfacial layer 230 eliminates thedirect contact and interface between the free layer 250 and the spacerlayer 220 to allow selected magnetic materials to be used for the freelayer 250.

FIG. 3B shows a different design using an interfacial magnetizationlayer. This device 200′ includes a free layer 250′ having aperpendicular magnetization 251′, a spacer layer 220′, an interfaciallayer 260′ in contact with the spacer layer 220′ and having aperpendicular magnetization 261′ and a fixed layer 210′ with a fixedperpendicular magnetization 211′. The interfacial layer 260′ is locatedbetween the spacer layer 220′ and the fixed layer 210′ to eliminate thedirect interfacing between the fixed layer 210′ and the spacer layer220′. The magnetization 261′ of the interfacial layer 260′ ismagnetically coupled to and pinned to the fixed magnetization 211′ ofthe fixed layer 210′.

FIG. 3C shows an example of a device that implements two interfaciallayers on opposite sides of the spacer layer to separate both the freelayer and the fixed layer from being in direct contact with the spacerlayer. This device 200″ includes a free layer 250″ having aperpendicular magnetization 251″, a spacer layer 220″, a firstinterfacial layer 230″ in contact with the spacer layer 220″ and havinga perpendicular magnetization 231″, a fixed layer 210″ with a fixedperpendicular magnetization 211″ and a second interfacial layer 260″with a perpendicular magnetization 261″. The first interfacial layer230″ is located between the spacer layer 220″ and the free layer 250″ toeliminate the direct interfacing between the free layer 250″ and thespacer layer 220″. The magnetization 231″ of the first interfacial layer231″ is magnetically coupled to the free magnetization 251″ of the freelayer 250″ to be switched along with the free layer 250″. The secondinterfacial layer 260″ is located between the spacer layer 220″ and thefixed layer 210″ to eliminate the direct interfacing between the fixedlayer 210″ and the spacer layer 220″. The magnetization 261″ of thesecond interfacial layer 260″ is magnetically coupled to and pinned tothe fixed magnetization 211″ of the fixed layer 210″.

In other implementations, one or more film stacks of two additionaladjacent layers are included between the spacer layer and the free layerand/or between the spacer layer and the fixed layer to engineer desiredproperties of the magnetic elements. Of the two additional adjacentlayers in one film stack, the first additional layer is an interfaciallayer in contact with the spacer layer. This interfacial layer is amagnetic layer with a “native” magnetization which is eitherperpendicular to the layer or, in absence of interaction with otherlayers, parallel to the interfacial layer and perpendicular to the fixedlayer magnetization. In the latter case, the magnetization of theinterfacial layer becomes perpendicular to the interfacial layer when itis magnetically coupled with other layers. The second additional layeris a connecting layer in contact with the interfacial layer on one sideand in contact with either the free layer or the fixed layer on theother side to provide magnetic coupling between the interfacial layerwith either the free layer or the fixed layer to ensure themagnetization of the interfacial layer to be perpendicular to theinterfacial layer. The connecting layer is a layer that is separate fromthe perpendicular layer and the interfacial layer and is physicallygrown in between of the perpendicular layer and the interfacial layer.The thickness of the interfacial layer can be made sufficiently large(e.g., greater than 1-2 nm to achieve a large TMR ratio.

FIG. 4A shows an example of a magnetic element 300 with perpendicularmagnetization having such additional layers. The free layer is the layer250 with a perpendicular magnetization 251 that can be switched betweentwo perpendicular and opposite directions. The fixed layer is the layer210 with a fixed perpendicular magnetization 211. The two additionallayers are magnetic layers 330 and 340 located between the free layer250 and the spacer layer 220. The magnetic layer 330 is an interfaciallayer with a sufficiently thickness to provide a high magnetization 331and the magnetic layer 340 is a connecting layer that is in contact withthe free layer 250 and the interfacial layer 330 to magnetically pullthe magnetization of the interfacial layer 330 to be perpendicular tothe interfacial layer 330.

The interfacial layer 330 in this example has its magnetization 331 inthe plane of the interfacial layer 330 when the layer 330 is freestanding and is not magnetically coupled with other layers. Theconnecting layer 340 has a structure to provide magnetic couplingbetween the free layer 250 and the interfacial layer 330 to ensure thatthe magnetization of the interfacial layer 330 be perpendicular to theinterfacial layer 330. For example, the connecting layer 340 can be madesufficiently thin to effectuate magnetic coupling that drives themagnetization of the interfacial magnetic layer from the its originalin-plane direction to the final direction perpendicular to the plane.The perpendicular magnetization of the interfacial layer 330 strengthensthe overall perpendicular anisotropy of the magnetic element and thusstabilizes the free layer 251 against thermal and magneticperturbations. The connecting layer 340 can be selected to reduce thedamping of either or both of the high magnetization interfacial layer330 and the free layer 250.

In addition, the connecting layer 340 provides a structural separationor buffer between the free layer 250 and the interfacial layer 330 topermit that the free layer 250 and the interfacial layer 330 havedifferent material structures. This function of the connecting layer 340provides flexibility in selecting materials for the free layer 250 andother layers to optimize enhance the properties of the final magneticelement 300. The connecting layer 340 can prevent the crystallineproperties of the free layer 250 from affecting the crystallinity of thetunneling junction barrier formed by the spacer layer 220 when made ofan insulating material. The present design eliminates the direct contactbetween the perpendicular free layer 250 and the barrier layer 220 toavoid correlation of the crystal properties of the free layer 250 andthe barrier layer 220. Therefore, different crystal properties (such aslattice type) of the layers 250 and 220 can be designed to enhance thespin-torque efficiency and TMR without being limited to restrictionsimposed by the compatibility of the layers 250 and 220. As an example,an epitaxial MgO (001) structure can be used as a high-quality tunnelingjunction barrier to improve the TMR ratio in STT device. The connectinglayer 340 can also facilitate inducing the desired perpendicularanisotropy in the high-polarization interfacial layer 330, and thusassisting the perpendicular free layer 250 to pull the magnetization ofthe high polarization interfacial layer 330 from the in-plane directionto the perpendicular direction.

The connecting layer 340 can be made from various materials. Someexamples include crystalline materials that include MgO with aresistance-area product lower than that of the spacer layer 220, such asMgO/Mn, MgO/Cr, MgO/V, MgO/Ta, MgO/Pd, MgO/Pt, MgO/Ru, and MgO/Cu.Amorphous materials may also be used to form the connecting layer 240,such as oxides SiOx, AlOx, and TiOx. Nitride materials can also beapplied to form the connecting layer 240, such as TiN, TaN, CuN, SiNx.The connecting layer 240 can also be formed by a crystalline matchmaterial such as Mn, Cr, V, Ru, Cu, Pt, Pd, Au, and Ta.

The interfacial magnetic layer 330 can be configured to exhibit highspin polarization and a low damping. As an example, when the spacerlayer 220 is MgO, the material for the interfacial layer 330 can beselected to create a high TMR ratio. As deposited, this interfaciallayer 330 has an in-plane anisotropy and its anisotropy becomesperpendicular to the layer when the multilayer structure is formed. Forexample, the interfacial layer 330 can include Fe, FeCo, CoFeB and amaterial with a high magnetization and crystallinity match with MgO.

FIG. 4B shows an example of a magnetic element 300′ having interfaciallayers on both sides of the spacer layer. This device 300′ includes afree layer 250′ having a perpendicular magnetization 251′, a spacerlayer 220′, a first interfacial layer 330′ between the spacer layer 220′and the free layer 250′ and having a perpendicular magnetization 331′, afixed layer 210′ with a fixed perpendicular magnetization 211′, a secondinterfacial layer 360 in contact with the spacer layer 220′, and aconnecting layer 370 between the second interfacial layer 360′ and thefixed layer 210′. The interfacial layer 330′ is located between thespacer layer 220′ and the free layer 250′ to eliminate the directinterfacing between the free layer 250′ and the spacer layer 220′. Themagnetization 331′ of the interfacial layer 330′ is magnetically coupledto the free magnetization 251′ of the free layer 250′ to switch with thefree layer 250′. The connecting layer 370 magnetically couples themagnetization 361 of the interfacial layer 360 to the fixed layer 210′and thus fixes the magnetization 361. The second interfacial layer 360and the connecting layer 370 are located between the spacer layer 220′and the fixed layer 210′ to eliminate the direct interfacing between thefixed layer 210′ and the spacer layer 220′.

FIG. 4C shows another example of a magnetic element 300″ that, inaddition to having a connecting layer and an interfacial layer betweenthe free layer and the spacer layer, implements a second connectinglayer and a second interfacial layer between the fixed layer and thespacer layer. As illustrated, the magnetic element 300″ includes a freelayer 250′ with a perpendicular magnetization 251′, a nonmagnetic spacerlayer 220′ and a fixed layer 210′ with a perpendicular magnetization211′. Similar to the design in FIG. 4A, between the free layer 250′ andthe spacer layer 220′, a first interfacial layer 330′ and a firstconnecting layer 340′ are formed. Between the fixed layer 210′ and thespacer layer 220′, a second interfacial layer 360 with a highpolarization and a second connecting layer 370 with a resistance-areaproduct lower than that of the spacer layer 220′ for providing couplingbetween the second interfacial layer 260′ and the fixed layer 210′ areformed.

Interfacial layer and/or the connecting layer in the fixed layer and/orthe free layer described above can also be applied to MTJ structureswith the fixed layer above the spacer.

FIG. 5 shows an exemplary device 400 having an array of magneticelements having at least one free layer having a perpendicularanisotropy. The device 400 includes an array of magnetic elements 410that are formed on a substrate. Each magnetic element 410 can beconfigured to have a perpendicular anisotropy based on the designs inFIGS. 3A,3B, 3C, 4A, 4B, and 4C described above. The device 400 alsoincludes circuitry with isolation transistors, read and write lines, andlogic circuitry for accessing individual magnetic elements 410. Thedevice 400 can be used in magnetic memory systems.

The above magnetic element designs can be implemented for switching ofthe free layer based on the spin torque transfer. FIGS. 6 and 7 describecircuitry for switching based on the spin torque transfer.

FIG. 6 illustrates a part of an exemplary magnetic device 500 thatincludes an array of unit cells. Each unit cell includes a magneticelement 501 based on the spin-transfer torque effect. A conductor line510 labeled as “bit line” is electrically coupled to the magneticelement 501 by connecting to one end of the magnetic element 501 tosupply an electrical drive current 540 through the layers of themagnetic element 501 to effectuate the spin-transfer torque effect inthe magnetic element 501. An electronic isolation device 530, such as anisolation transistor, is connected to one side of the magnetic element501 to control the current 540 in response to a control signal appliedto the gate of the transistor 530. A second conductor line 520 labeledas “word line” is electrically connected to the gate of the transistor530 to supply that control signal. In operation, the drive current 540flows across the layers in the magnetic element 501 to changemagnetization direction of the free layer when the current 540 isgreater than a switching threshold which is determined by materials andlayer structures of the magnetic element 501. The switching of the freelayer in the magnetic element 501 is based on the spin-transfer torquecaused by the drive current 540 alone without relying on a magneticfield produced by the lines 510 and 520 or other sources.

The magnetic element 501 based on the spin-transfer torque effect can beimplemented in various configurations, such as an MTJ, a spin valve, acombination of an MTJ and a spin valve, a combination of two MTJs andother configurations. Each of the free and pinned layers can be a singlemagnetic layer or a composite structure of multiple layers magneticallycoupled together.

FIG. 7 shows an exemplary circuit that operates an arrayed magneticmemory device based on spin-transfer torque switching. Each cell 610 isconnected in series to a select transistor 620 which corresponds to theisolation device 530 in FIG. 6. As illustrated, a bit line selector 601,a source line selector 602 and a word line selector 603 are coupled tothe cell array to control the operations of each cell.

While this document contains many specifics, these should not beconstrued as limitations on the scope of an invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis document in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or a variation of a subcombination.

Only a few implementations are disclosed. Variations and enhancements ofthe described implementations and other implementations can be madebased on what is described and illustrated in this document.

What is claimed is:
 1. A device, comprising: a magnetic elementincluding: a fixed layer having a fixed layer magnetization fixed in adirection perpendicular to the fixed layer; a free layer that isparallel with the fixed layer and has a free layer magnetization that isperpendicular to the free layer and is changeable relative to the fixedlayer magnetization; a nonmagnetic spacer layer between the fixed layerand the free layer; a first interfacial layer in contact with thenonmagnetic spacer layer and between the fixed layer and the nonmagneticspacer layer, the first interfacial layer having a native magnetizationwhich is, in the absence of coupling with other layers, parallel to thefirst interfacial layer and perpendicular to the fixed layer; aconnecting layer between and in contact with both the first interfaciallayer and the fixed layer, the connecting layer being structured (i) toinduce perpendicular anisotropy in the first interfacial layer and (ii)to provide magnetic coupling between the fixed layer and the firstinterfacial layer, such that (i) the induced perpendicular anisotropytogether with (ii) the magnetic coupling change the magnetization of thefirst interfacial layer from being parallel to the first interfaciallayer to being perpendicular to the first interfacial layer; and asecond interfacial layer between and in contact with both thenon-magnetic spacer layer and the free layer, the second interfaciallayer being magnetically coupled with the free layer.
 2. The device asin claim 1, wherein the connecting layer is a crystalline material thatincludes MgO.
 3. The device as in claim 2, wherein the connecting layeris structured to have a resistance-area product less than aresistance-area product of the spacer layer.
 4. The device as in claim2, wherein the connecting layer is made from one combinations of MgO andMn, MgO and Cr, MgO and V, MgO and Ta, MgO and Pd, MgO and Pt, MgO andRu, and MgO and Cu.
 5. The device as in claim 1, wherein the connectinglayer is an amorphous material.
 6. The device as in claim 5, wherein theconnecting layer is made from an oxide.
 7. The device as in claim 6,wherein the oxide is one of silicon oxide, aluminum oxide, or titaniumoxide.
 8. The device as in claim 5, wherein the connecting layer is madefrom a nitride.
 9. The device as in claim 8, wherein the nitride is oneof titanium nitride, tantalum nitride, copper nitride, or siliconnitride.
 10. The device as in claim 1, wherein the connecting layer is acrystalline metal selected from the group consisting of Mn, Cr, V, Ru,Cu, Pt, Pd or Ta.
 11. The device as in claim 1, wherein: the connectinglayer is a crystalline material that comprises MgO, and the firstinterfacial layer comprises CoFeB.
 12. The device as in claim 1, whereinthe first and second interfacial layers each has a lattice structurethat is compatible to a lattice structure of the nonmagnetic spacerlayer.
 13. The device as in claim 1, wherein the first and secondinterfacial layers each comprises Fe and Co.
 14. The device as in claim1, wherein the first interfacial layer comprises CoFeB.
 15. The deviceas in claim 1, wherein the first and second interfacial layers each hasa thickness larger than 1 nanometer.
 16. The device as in claim 15,wherein the second interfacial layer has the thickness larger than 2nanometers.
 17. The device as in claim 1, wherein the fixed layer has athickness larger than the thickness of the first interfacial layer andthe free layer has a thickness larger than the thickness of the secondinterfacial layer.
 18. The device as in claim 1, wherein the secondinterfacial layer is magnetically coupled with the free layer such thata magnetization of the second interfacial layer is parallel to the freelayer magnetization.
 19. The device as in claim 18, wherein the secondinterfacial layer has a native magnetization which is, in absence ofinteraction with the free layer, parallel to the second interfaciallayer and perpendicular to the fixed layer magnetization.
 20. The deviceas in claim 19, wherein the second interfacial layer comprises CoFeB.21. The device of claim 1, wherein: the free layer includes at least oneferromagnetic material Ni, Fe, Co, or combinations thereof; Pd, Pt, orcombinations thereof; and combined with at least one nonmagneticmaterial X; wherein an atomic percentage of free layer ferromagneticmaterial Ni, Fe, Co, or combinations thereof equals an atomic percentageof free layer material Pd, Pt, or combinations thereof; wherein the freelayer includes between zero and fifty atomic percent of nonmagneticmaterial X; wherein X includes at least one of Ti, Zr, Hf; V, Nb, Ta,Cr, Mo, W, Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu, B, C, N, O, Al, Si,P, S, Ga, Ge, In, Sn, Gd, Tb, Dy, Ho, Nd, or a transition metalsilicide.
 22. The device of claim 1, wherein: the free layer includes atleast one ferromagnetic material Ni, Fe, Co, or combinations thereof;Pd, Pt, or combinations thereof; and combined with at least twononmagnetic materials X1 and X2; wherein an atomic percentage of freelayer ferromagnetic material Ni, Fe, Co, or combinations thereof equalsan atomic percentage of free layer material Pd, Pt, or combinationsthereof; wherein the free layer includes between zero and fifty atomicpercent of nonmagnetic material X1; wherein the free layer includesbetween zero and fifty atomic percent of nonmagnetic material X2;wherein X1 includes at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W,Pt, Pd, Ir, Rh, Ru, Os, Re, Au, Ag, Cu, Gd, Tb, Dy, Ho, Nd; wherein X2includes at least one of B, C, N, O, Al, Si, P, S, Ga, Ge, In, Sn, or atransition metal silicide.
 23. The device of claim 1, wherein the fixedlayer comprises two magnetic sublayers separated by a non-magneticlayer, such that the two magnetic sublayers are antiferromagneticallycoupled.
 24. The device of claim 1, wherein the fixed layer comprisestwo magnetic sublayers separated by an oxide layer, such that the twomagnetic sublayers are antiferromagnetically coupled.
 25. The device asin claim 1 further comprising: a substrate on which the magnetic elementis formed; a capping layer; and a seed layer, wherein if the fixed layeris placed between the free layer and the substrate, then the cappinglayer is over the free layer, and the seed layer is between thesubstrate and the fixed layer, else if the free layer is placed betweenthe fixed layer and the substrate, then the capping layer is over thefixed layer, and the seed layer is between the substrate and the freelayer.
 26. The device as in claim 25, wherein either the capping layeror the seed layer or both comprises a multilayer structure.
 27. Thedevice as in claim 25, wherein either the capping layer or the seedlayer or both comprises crystalline structure.
 28. The device as inclaim 25, wherein either the capping layer or the seed layer or bothcomprises amorphous structure.
 29. The device as in claim 25, whereineither the capping layer or the seed layer or both comprises a metal.30. The device as in claim 25, wherein either the capping layer or theseed layer or both comprises an oxide.
 31. The device as in claim 25,wherein either the capping layer or the seed layer or both comprisesnonmagnetic material.
 32. The device as in claim 25, wherein either thecapping layer or the seed layer or both comprises magnetic material. 33.The device as in claim 25, wherein either the capping layer or the seedlayer or both comprises in-plane anisotropy.
 34. The device as in claim25, wherein either the capping layer or the seed layer or both comprisesperpendicular anisotropy.
 35. The device as in claim 1 furthercomprising: a circuit that is coupled to the magnetic element andsupplies a current to flow through layers of the magnetic element in adirection perpendicular to the layers to switch the magnetization of thefree layer.
 36. A device, comprising: a magnetic element arrayincluding: a substrate; and a plurality of magnetic elements formed onthe substrate, each magnetic element comprising a fixed layer having afixed layer magnetization fixed in a direction perpendicular to thefixed layer, a free layer that is parallel with the fixed layer and hasa free layer magnetization that is perpendicular to the free layer andis changeable relative to the fixed layer magnetization, a nonmagneticspacer layer between the fixed layer and the free layer; a firstinterfacial layer in contact with the nonmagnetic spacer layer andbetween the fixed layer and the nonmagnetic spacer layer, the firstinterfacial layer having a native magnetization which is, in the absenceof coupling with other layers, parallel to the first interfacial layerand perpendicular to the fixed layer, a connecting layer between and incontact with both the first interfacial layer and the fixed layer, theconnecting layer being structured (i) to induce perpendicular anisotropyin the first interfacial layer and (ii) to provide magnetic couplingbetween the fixed layer and the first interfacial layer, such that (i)the induced perpendicular anisotropy together with (ii) the magneticcoupling change the magnetization of the first interfacial layer frombeing parallel to the first interfacial layer to being perpendicular tothe first interfacial layer, and a second interfacial layer between andin contact with both the non-magnetic spacer layer and the free layer,the second interfacial layer being magnetically coupled with the freelayer; and a circuit that is coupled to the magnetic element array andsupplies a current to flow through layers of each magnetic element in adirection perpendicular to the layers to switch the magnetization of thefree layer based on spin torque transfer between two magnetizationdirections.
 37. The device as in claim 36, wherein the connecting layeris a crystalline material that includes MgO.
 38. The device as in claim36, wherein the first and second interfacial layers each comprisesCoFeB.
 39. The device as in claim 36, wherein the first and secondinterfacial layers each has a thickness larger than 1 nanometer.
 40. Thedevice as in claim 39, wherein the second interfacial layer has thethickness larger than 2 nanometers.
 41. The device as in claim 36,wherein the fixed layer has a thickness larger than the thickness of thefirst interfacial layer and the free layer has a thickness larger thanthe thickness of the second interfacial layer.
 42. A device, comprising:a magnetic element including: a fixed layer having a fixed layermagnetization fixed in a direction perpendicular to the fixed layer; afree layer that is parallel with the fixed layer and has a free layermagnetization that is perpendicular to the free layer and is changeablerelative to the fixed layer magnetization; a nonmagnetic spacer layerbetween the fixed layer and the free layer; a first interfacial layerbetween the fixed layer and the nonmagnetic spacer layer and in contactwith the nonmagnetic spacer layer, the interfacial layer comprisingCoFeB with a native magnetization which is, in absence of coupling withother layers, parallel to the interfacial layer and perpendicular to thefixed layer magnetization; a connecting layer between and in contactwith both the first interfacial layer and the fixed layer, theconnecting layer being a crystalline material that includes MgO whichinduces perpendicular anisotropy in the first interfacial layer, suchthat the magnetization of the first interfacial layer having the inducedperpendicular anisotropy changes, via magnetic coupling with the fixedlayer, from being parallel to the first interfacial layer to beingperpendicular to the first interfacial layer; and a second interfaciallayer between and in contact with both the non-magnetic spacer layer andthe free layer, the second interfacial layer being magnetically coupledwith the free layer; a substrate on which the magnetic element is formedto place the fixed layer between the free layer and the substrate or toplace the free layer between the fixed layer and the substrate; and acircuit that is coupled to the magnetic element and supplies a currentto flow through layers of the magnetic element in a directionperpendicular to the layers to switch the magnetization of the freelayer.